密度演化算子在量子系综演化中的应用  

Application of density evolution operator in quantum ensemble evolution

作　　者：韩琦[1] 韦仁童 何明珍[1] 郭婷[1] 

机构地区：[1]西北师范大学数学与统计学院,甘肃兰州730070

出　　处：《江苏师范大学学报（自然科学版）》2017年第1期73-75,共3页Journal of Jiangsu Normal University：Natural Science Edition

基　　金：国家自然科学基金资助项目(11061032;1261023-G0114)

摘　　要：讨论在4种情况下,用量子系综密度演化算子描述量子系统状态,并证明了存在包含ρ支集中任一状态的最小系综,使这一状态以固定概率出现.最后证明了当密度算子为纯态时,Bloch向量的模为1;为混合态时,Bloch向量的模小于1.The quantum system state described by quantum ensemble density evolution operator in four cases is discussed,and the existence of a minimal ensemble which includes any state of ρ support and makes the state appear in a fixed probability of piis proved.Finally,that the module of Bloch vector equals to 1 when the density operator is pure state,and the module of Bloch vector is less than 1 when the density operator is mixed state are also proved.

关 键 词：系综 密度演化算子 酉自由度 Bloch向量 

分 类 号：O211.4[理学—概率论与数理统计]